Spool valve for rock drills



Jan. 1, 1924 Y A 1,419,356-

L.. C. BAYLES SPOOL VALVE FOR ROCK DRILLS' Filed March129..192z

HIS ATToNEY Patented Jan. l, 1924.

UNITED STAT LEWIS C. BAYLES,'OF EASTON, PENNSYLVANIA, ASSIGNOR TO INGERSOLL-I/ANDCOM- PANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

l SPOOL VALVE FOR ROCK DRILLS.

Application filed March 29, 1922. Serial No. 547,872.V

To all whom t may concern.'

Be itknown that I,Lnw1s C. BAYLns, a citizen of the United States, and a resident of Easton, county of Northampton, and State of Pennsylvania, have invented a certain Spool Valve for Rock Drills, of which the following is a speciiication accompanied by drawings.l

This invention relates to fluid actuated hammer drills but more vparticularly to a motive fluid distributing Yvalve of the spool type, such as disclosed in my co-pendingV application, Serial N o. 451,661, filed March l2, 1921, for controlling both the inlet and exhaust from both ends of the cylinder of the machine.

Valves of this type, especially for a large machine, are ordinarily of substantial size and weight, and impact with considerable force against the valve stops which limit t-heir movement, which may injure the valve faces, in case the impact takes place on such faces, or cause breakage.

The objects of the present invention are to produce a valve of the type described, which is light a-ndstrong and is at the same time provided with stops which limit the valve movement without permitting the edges of the end faces of the valve to abut against adjacent parts of the valve structure, so that control of the motive Huid at the end faces is eected solely by sliding contact between the valve and the part or parts within which it is contained. c

Further objects of the invention are to enable the impact of the valve to be cushioned in a valve structure which may be readily assembled, but securely held in alignment in the valve chest by simple means capable of withstanding severe usage.

The invention is shown in one of its preferred forms in the accompanying drawings, in which Figure l is a top plan ,vie-w, partly broken away and partly in horizontal section through the valve chest, of so much of a rock drill as will serve to'illustrate the invention.

Figure 2 is a diagrammatic longitudinal sectional elevation through the valve chest and a portion of the cylinder, with the chest and cylinderconventionally shown in the same plane for clearness of illustration, and Y Figure 3 is a detail perspective view of a form of cushioning device.

Referring to the drawings, a fluid actuated rockdrill ofthe hammer type is shown, havingthe cylinderl A, the front head B and the back head C, adapted to by the usual side bolts D. E extending into the front head,VV is adapted to receive the impact blows of the hammer piston F (see Figure 2) reciprocating in the cylinder A and provided with'the reduced shank or extension G, guided in thefront cylinder Washer H. l i

The supply and distribution of motive is controlled by iuid for operating the tool the usual throttle valve J and `the spool valve K, mounted in the valve chest L, which is adapted to be secured on the side of thev cylinder, as by meansl of the bolts O. The throttle valve J controls the inlet P and is provided with the operating handle 1s limited in its rotary movement a stop b Motive Huid enters at the inlet passesv through the throttle valve J to the supply passage S in the valve chest which branches and leads to the inlet ports T .controlled by the distributing valve K. Y

The construction and operation of the spool valve K and thedistribution of motivel y luidin the machine can more readily be 'f described and followed by Areference to the` conventiontal diagrammatic view shown in Figure 2 in which the valve is shown longitudinally of the cylinder A and the various ports and simplicity, toV all be in one longitudinal plane, the relative positions ofthe ports however, remaining the same as in the actual construction indicated inFigure l. Figure of its stroke and about to start forwardly.

In the construction of the valve K and its associated parts, whichform the principal subject matter of the present invention, the cylinder A and valve chest L areV with suitable ports and passages, for distributing motive fluid to both ends of the cylinder and for exhausting the fluid from the cylinder. The spool valve K is of special construction and is formed or recessed end faces ct and b which utilized to, control the inlet toboth ends of the .cylindeig While an enlarged central flange@ controls'the exhaust from bothl ends of the cylinder, ing d at the center of the valve permits a bolt c to be placed through the valve for be held together The drill steel' Q which passages are assumed, for Y with hollowV are Y oc V V2 shows the piston F at the rearward end 'Y formed and a central bore or open`4 Y holding the parts of the valve structure togetherand within the valve chest.

The valve operates in the flanged bushings X and Y which are adapted to be inserted from opposite ends into the bore of the valve chest. These bushings as shown, are spaced apart or separated at their inner opposed faces, leaving a space Z forming an exhaust passage through the chest communicating with the exhaust port f and after the bushings and valve have been assembled in the valve chest, the bolt e is tightened to hold the parts in place, and form a guide for the valve.

By making the endsv of the valve K hol low, the valve isma-de as light asl practically possible, and thisalso ad'ords means for providing valve stops, preferably in the form of sleeves g and 7L within the valve bushings, against which stops the bottom portionsj and c of the recessed end faces ofthe valve are adapted to abut for limiting the movement of the valve, without permitting the edges o and p of the end faces to abut against adjacent parts of the bushings or stops.A By this means, control of the motive fluid at the end solely by sliding contact between the valve yand the bushings, because the edges o and of the valve are permitted to' over-run the inlet ports which they control. The impact of the valve against the stops takes place between the solid central portion ofk the valve and the ends of, the stops,l and the thinner and lighter edges o and pof the end faces are protected from impact.

ln order to further insure the valve against breakage, suitable cushioning means are provided for the stops g and h of any suitable type or form, and inv this instance, metallic cushioning devices in thev form of bent washers g and r are provided between the stops g and 7L andthe cover plates t andV u. placed over the ends of the valve bushings X and Y respectively. A detail view of one of these bentspring washers is shown in Figure 3,`but any other suitable form of buffers could be used. The actual deformation of the buffers is slight and they are for the purpose of softening the blow of impact of the valve against the stops.

The valve chest L and valve bushings, in addition to the functions supplied by the inlet ports T and the exhaust port f located between them at one side of the chest, aff yfords communication with admission ports .c and fw leading to points near the forward andfrearward ends of the cylinder, and also affordsconimunication with exhaustports m and y opening into the. cylinder at points be-` tween the admission ports 'v and w and the centei` of the cylinder. For these purposes,

the valve bushings X andjYV are provided with supply passages connectingA the valve chest inlet ports T 'andk the cylinder admis.-

.valve in either extreme position.

faces ofthe valve is effectedl sion ports n and w, and the recessed end faces c and b ofthe valve K control the said supply passages through the valve bushings and by this means control the inlet to both ends ofthe cylinder through the. admission ports, while the enlarged central flange c of the valve controls the exhaust passage or space Z between the opposed faces of the bushings and thuscontrols the exhaust from both ends of the cylinder through the exhaust ports. Y

The opening l through the center of the valve K is made slightly larger in diameter than the diameter ofthe bolt'c so as to pre-A vent binding, the flow of air through this space being cut olf by the stops when the. The period in which the valve is in intermediate position is so short that the leakage through this space will not affectA the action.

` In the operation of the machine, let it be assumed that the piston` F is inthe position indicated in. Figure '2 at the rearward end of its stroke. and it is starting forwardly. The valve K has moved over to the POSitien indicated in said figure and motive fluid is being admitted from the inlet port T through, the admission port w to the rearward. end of' the cylinder as indicated by the arrows. The exhaust from the forwardy end of the cylinder isopen tlirouglitheexhaust passage m and the exhaust port f to atmosphere. As the piston in its forward travel uncovers the exhaust passage y, leading tothe rearward end ofthe cylinder, andl closes the exhaust passage m fromv thefor-v ward endv of the cylinder, the motive fluid, inl

the rearward endof the cylinder'A willpass. through thel passage y and exert a pressure on the forward face of theflange c substanf.

tially equalto, but preferably lessfthan, andopposed to that exerted by the motive Huidy onthe end face a, and bottom surface y' ofL the recessed end, so that the pressureV inv frontof .the end face` b of the valve, due. to compression inthefcylinder through the port o, will readily throw the valve rearwardlvV to the opposite positiontol that indicatedin Figure 2. thereby closing the supply of mo.

tive fluid to the rearward vend of the. cylin-` der, opening the exhaust to the saidy rearwardl end of the cylinder, and alsoopening the supply of` motive fluid to the forwardYA end of the cylinderin front o f the pistonA l?V through the inlet port T and the admission,

port e.v rlhe piston then starts rearwardly andthe cycle is repeated,

IY claim:

lf Ina fiuid actuated, roel; drill of, the.

hammer type, thecombination of a cylinder and a reciprocating piston, a valve chest,-

connected` to said' cylinder, inletportsand a central exhaust port between said inlet: ports at oney side of the chest, admission ports in the cylinder corresponding to and,

supplied from the said valve chest inlet ports, exhaust ports in the cylinderV between the said admission ports and leading to the f sion ports, a cylindrical valve movable in said bushings and having an enlarged central flange controlling the exhaust passage between the bushingsv and also having reduced and hollowed or Vrecessed end faces controlling the said supply passages through the bushings, stops within the bushings projecting into the valve against which the bottom portions of the recessed end faces of the valve are adapted to abut for limiting the movement of the valve, and a bolt passing through the bushings, the stops and the valve for holding the parts together, whereby the valve is also guided on the bolt and actuated in one direction or the other by pressure built up through the admission ports of the cylinder and the supply passages of the bushings behind the end faces of the valve, due to compression in the cylinder.

2. In a. fluid actuated rock drill of the hammer type, the combination of a cylinder and ay reciprocating piston, a valve chest connected to said cylinder, inlet ports and a central exhaust port between said inlet ports at one side of the chest, admission ports in the cylinder corresponding to and supplied from the said valve chest inlet-v ports, exhaustports in the cylinder between the said admission ports and leading to the central ortion of the chest, valve bushings in the cliest spaced apart at their inner opposed faces to form an exhaust passage through the chest, supply passages in the bushings connecting the valve chest inlet ports and the corresponding cylinder admission ports, a cylindrical valve movable in said bushings and having an enlarged central flange controlling the exhaust passage between the bushings and also having reduced and hollowed or recessed end faces controlling the said supply passages through the bushings, stops within the bushings projecting into the valve against which the bottom portions of the recessed end faces of the valve are adapted to abut for limiting the movement of the valve, cushioning means for said stops located at the vouter ends of the stops, and a bolt passing through the bushings, stops, cushioning means, and the valve for holding the parts together, whereby the valve is also guided on the bolt and actuated in one direction or the other by pressure built up through the admission ports of the cylinder and the supply passages of the bushings behind the end facesof the valve, due .to compression in the cylinder.

3. Inl a fluidactuatedroclr drill of the hammer type, the combination of a ,cylin- `der anda reciprocating piston, a valve chest connectedV4 to said cylinder, inlet ports andv a .central exhaust, port `between said inlet ports at one side ofthe chest, admissionvv ports in the ,cylinder corresponding to and supplied from. thevv said valve chest ,inlet ports,*exhaust por-ts the saidadmission central portionv of in thepchest spaced apart at their inner opposed faces to `form an exhaust passage through the chest, supply passages in the bushings connecting the valve chest inletl ports and the corresponding cylinder admission ports, a cylindrical valve movable in said bushings and having an enlarged central flange controlling the exhaust passage between the bushings and also having reduced and hollowed or recessed end faces controlling the said supply passages through the bushings, stops within the bushings projecting into the valve against which the bottom portions of the recessed end faces of the valve are adapted to abut for limiting the movement of the valve, without permitting the edges of said end faces to abut against adjacent parts of bushingsv or stops, and thereby effecting control of fthe motive fluid through the Vinlet ports at the end in the cylinder between ports and leading-'to the Vfaces of the valve, solely by sliding contact between Ithe valve and the bushings, cushioning means for said stops located at lthe outer en s o-f the stops, and a bolt passing through the bushings, stops, cushioning means, and the valve for holding the parts together, whereby the valve is also guided on the bolt and actuated inone direction or the other `by pressure built up through the admission ports of the'cylinder and the supply passages of the bushings behind the end faces of the valve, due tocompression in the cylinder.

4l. In a -luid actuated rock drill of the hammer type, the combination of a cylinder and a reciprocating piston, a valve chest connected to said cylinder', inlet ports and a central exhaust port between said inlet ports at one side of the chest,r admission ports in the cylinder corresponding to and supplied from the said valve chest inlet ports, exhaust ports in the cylinder between the said admission ports and leading to the central portion of the chest, valve bushings in the chest spaced apart at their inner opposed facesto forman exhaust passage through the chest, supply `passages in the bushings connecting the valve chest inlet ports and the corresponding cylinder admission ports, a cylindrical valve movable in said bushings and having an enlarged central flange controlling the exhaust pasthe chest, valve bushings.

sage between the bushings and also having reduced and hollowed or recessed end Jfaces controlling the said supply passages through the bushings, stopswithin the bushings projeoting into vthe valve against Which the bottom portions of the recessed end faces of the valve are adapted to abut for limiting the vmovement of the Valve Without permitting the edges of said' ends faces to abut against adjacent parts of bushings or stops andwthereby effecting control ofthe motive fluid through the inlet ports at the end faces of the valve, solely by sliding contact between the valve and the bushings, l

cover plates Yfor the bushings, cushioning means for said stops'located vbetween the stops and the cover-plates', and a bolt pass-- ing through. the cover plates, bushings, cushioning' means, stops, yand the'va-lve for holding tie `parts together, whereby the valveis also guided'on the boltand actuated in one direction or the other by pressure built up through the admission ports of the cylinder and the supply passages of the bushings behind the end faces of the' valve,

due to compression in `the cylinder.v

In testimony whereof I have signed this specification.

LEWIS C. BAYLES. 

